Analytical and numerical study of a circular cavity subjected to plane and cylindrical P-wave scattering

Dynamic stress concentration has been widely considered as an important factor that dominates the damage of underground cavities. To obtain the influence of wavefront curvature on the dynamic response around the circular cavity, the dynamic stress concentration near the cavity caused by the plane P-wave and cylindrical P-wave scattering is investigated based on the wave function expansion methods and Fourier transform. A three-dimensional numerical finite element model is subsequently established to simulate the dynamic damage and its influencing factors, including the period t0 of the incident wave and the initial lateral pressure coefficient γ, around the underground cavity subjected to plane P-wave and cylindrical P-wave. The results indicate that an obvious dynamic stress concentration occurs around the cavity under dynamic stress disturbance. The dynamic stress concentration factors (DSCFs) caused by the cylindrical P-wave is larger than that caused by the plane P-wave, and the obvious tensile stress concentration, which is equivalent to the compressive stress concentration, only occurs under the cylindrical P-wave. Furthermore, the failure characters of the cavity under different initial static stresses and dynamic incident loadings are simulated using the multiphysics software LS-DYNA, indicating that the dynamic failures are related to the initial static pressure coefficients, period of incident wave, and incident wavefront curvature. The plastic failure under the plane P-wave appears initially at the compressive concentration areas while the initial failure caused by the cylindrical P-wave occurs at the tensile concentration areas.